One previously proposed motor for use in a power window system includes: a motor arrangement for generating a rotational force; a speed reducing arrangement formed by housing a speed reducing mechanism in a gear housing; a control circuit board over which electrical circuit components are mounted; and a connector portion to which an external connector is fitted (see, for example, Japanese Unexamined Patent Publication No. 2000-220344).
Water droplets splashed onto a glass of a door can enter the interior of the door. Thus, a motor main body is provided with a drip-proof structure for protecting its electrical system. In the motor described in the above publication, a grommet, which covers an outer peripheral surface of the external connector, is formed separately from the gear housing, in which the connector portion is formed integrally. The grommet is fitted to the connector portion, so that the external connector is water proofed. In this way, a detachment restraining construction and a drip-proof structure are formed between the connector portion and the grommet.
More specific description will be given. The connector portion is provided on its outer peripheral surface with a plurality of engaging projections, and the grommet is provided with engaging holes corresponding to the engaging projections. The detachment restraining construction is thereby formed. The grommet is provided on its inner peripheral surface with a plurality of annular lip seal portions that are circumferentially closed and abutted against the side surface of the connector portion. Further, the grommet is provided on its outer peripheral surface with projected abutting portions. The drip-proof structure is thereby formed.
However, to make the detachment restraining construction and the drip-proof structure reliable, the following means are taken: a plurality of recesses and projections are formed on the outer peripheral surface of the connector portion, the inner peripheral surface of the grommet, and the like. This complicates the shapes of the connector portion and the grommet. Since the gear housing having the connector portion and the grommet are molded with metal molds and the like, a complicated shape raises the tooling cost and the like. This causes disadvantages associated with production cost.
An extremely complicated shape makes it difficult to mold a gear housing having a connector portion or a grommet from one item. Therefore, there are cases where, since the detachment restraining construction and the drip-proof structure are formed, limitations are imposed on other parts in terms of design.
The shape of an external connector is modified according to the specifications for the motor. For this reason, when the connector portion into which the external connector is fitted is integrally formed on a gear housing, a problem arises. The design of the entire gear housing must be reviewed in accordance with the shape of the external connector.
The present invention has been made to solve the above disadvantages. An object of the present invention is to achieve a high degree of design freedom and to provide a motor having a drip-proof structure of a relatively simple configuration and to provide a method of manufacturing such a motor.